Hydrophilic crosslinked modified organopolysiloxanes and contact lenses made therefrom are described in U.S. Pat. No. 4,153,641, issued May 8, 1979 to Bausch and Lomb, Incorporated. The hydrophilic crosslinked organopolysiloxanes described therein are obtained from the polymerization of a hydroxyalkylmethacrylate, i.e., 2-hydroxypropylmethacrylate, in the presence of a modified organopolysiloxane. These known modified organopolysiloxanes are diorganopolysiloxanes and the so-called IPN systems.
Also, U.S. patent application Ser. No. 895,535, filed Apr. 13, 1978 now U.S. Pat. No. 4,198,165 describes a process for the preparation of crosslinked, modified organopolysiloxanes by polymerizing at least one monomer having at least one aliphatic multiple bond, in the presence of free radical initiators and a crosslinkable or crosslinked organopolysiloxane containing at least 40 mol percent of monoorganosiloxane units. However, the aforementioned U.S. application does not disclose using hydroxyalkylmethacrylates or hydroxyalkylacrylates.
Compared to the modified organopolysiloxanes known heretofore, the modified organopolysiloxanes of this invention have the advantages that they can be prepared from organopolysiloxanes which are readily available. Moreover, the modified organopolysiloxanes of this invention are more rigid; thus contact lenses made therefrom or containing such modified organopolysiloxanes enhance the correction of visual deficiencies which are attributable to a deformation of the cornea, for example astigmatism.
Therefore, it is an object of this invention to provide hydrophilic modified organopolysiloxanes. Another object of this invention is to provide crosslinked hydrophilic modified organopolysiloxanes. Still another object of this invention is to provide crosslinked modified organopolysiloxanes which are rigid and may be used to make contact lenses. A further object of this invention is to provide a process for preparing crosslinked hydrophilic modified organopolysiloxanes.